The semiconductor manufacturing industry is now facing serious challenges in achieving defect detection rates with acceptable throughput and accuracy. With conventional bright-field and dark- field inspection methods now at their limits, it has become essential to explore alternative optical methods such as angle-resolved scatterfield microscopy, 193 nm short wavelength solutions, and coherent illumination. In this presentation we evaluate new optical technologies capable of extending high throughput defect inspection beyond the 22 nm node. We investigate source optimization for angle and polarization resolved illumination, measurement wavelengths down to 193 nm and a new approach for three-dimensional optical defect inspection validated with electromagnetic simulations and in the laboratory.